add depth calibration params to Yolo26Depth API

components/nn/include/maix_nn_yolo26_depth.hpp

@@ -187,11 +187,16 @@ namespace maix::nn
          * @param fit image resize fit mode if input image not equal to model' input size,
          *            will auto resize to model's input size then detect, and recover to image input size.
          *            Default Fit.FIT_CONTAIN, see image.Fit.
+         * @param cal_a calibration scale factor a, the depth is converted by d_real = exp(a * log(d) + b).
+         *            Default 1.0 (no calibration). Set both cal_a/cal_b to fit your camera/scene.
+         * @param cal_b calibration offset b, see cal_a. Default 0.0 (no calibration).
          * @throw If error occurred, will raise err::Exception, you can find reason in log, mostly caused by args error or hardware error.
-         * @return result, a tensor.Tensor object. If in dual_buff mode, value can be None(in Python) or nullptr(in C++) when not ready. In C++, you need to delete it after use.
+         * @return result, a tensor.Tensor object with calibrated depth in meters. If in dual_buff mode, value can be None(in Python) or nullptr(in C++) when not ready. In C++, you need to delete it after use.
          * @maixpy maix.nn.YOLO26Depth.get_depth
+         * @maixcdk maix.nn.YOLO26Depth.get_depth
          */
-        tensor::Tensor *get_depth(image::Image &img, image::Fit fit = image::FIT_CONTAIN)
+        tensor::Tensor *get_depth(image::Image &img, image::Fit fit = image::FIT_CONTAIN,
+                                  float cal_a = 1.0f, float cal_b = 0.0f)
         {
             if (_model == nullptr) return nullptr;
             std::unique_ptr<tensor::Tensors> outputs(_model->forward_image(img, {}, {}, fit, false, false));
@@ -205,6 +210,7 @@ namespace maix::nn
             _output_h = info.height;
             _output_w = info.width;
             tensor::Tensor *result = new tensor::Tensor(t->shape(), t->dtype(), t->data(), true);
+            _apply_calibration((float *)result->data(), info.width * info.height, cal_a, cal_b);
             return result;
         }
 
@@ -217,14 +223,19 @@ namespace maix::nn
          * @param cmap Color map used convert grayscale distance estimation image to RGB image.
          *             Diiferent cmap will influence finally image.
          *             Default image.CMap.JET (near red/yellow, far blue).
+         * @param cal_a calibration scale factor a, the depth is converted by d_real = exp(a * log(d) + b).
+         *            Default 1.0 (no calibration). Set both cal_a/cal_b to fit your camera/scene.
+         * @param cal_b calibration offset b, see cal_a. Default 0.0 (no calibration).
          * @throw If error occurred, will raise err::Exception, you can find reason in log, mostly caused by args error or hardware error.
-         * @return result, a image::Image object. If in dual_buff mode, value can be None(in Python) or nullptr(in C++) when not ready. In C++, you need to delete it after use.
+         * @return result, a image::Image object with calibrated depth heatmap. If in dual_buff mode, value can be None(in Python) or nullptr(in C++) when not ready. In C++, you need to delete it after use.
          * @maixpy maix.nn.YOLO26Depth.get_depth_image
+         * @maixcdk maix.nn.YOLO26Depth.get_depth_image
          */
         image::Image *get_depth_image(image::Image &img, image::Fit fit = image::FIT_CONTAIN,
-                                      image::CMap cmap = image::CMap::JET)
+                                      image::CMap cmap = image::CMap::JET,
+                                      float cal_a = 1.0f, float cal_b = 0.0f)
         {
-            std::unique_ptr<tensor::Tensor> depth(get_depth(img, fit));
+            std::unique_ptr<tensor::Tensor> depth(get_depth(img, fit, cal_a, cal_b));
             if (!depth) return nullptr;
             return depth_to_image(*depth, img.width(), img.height(), fit, cmap);
         }
@@ -392,6 +403,22 @@ namespace maix::nn
             return transform;
         }
 
+        /**
+         * Apply log-affine depth calibration in place: d_real = exp(a * log(d) + b).
+         * With default a=1, b=0 the data is unchanged.
+         */
+        void _apply_calibration(float *data, int count, float cal_a, float cal_b)
+        {
+            if (cal_a == 1.0f && cal_b == 0.0f)
+                return;
+            for (int i = 0; i < count; i++)
+            {
+                float d = data[i];
+                if (std::isfinite(d) && d > 0)
+                    data[i] = expf(cal_a * logf(d) + cal_b);
+            }
+        }
+
         /**
          * Convert depth map to RGB888 heatmap: disparity(1/depth) + min-max normalize + cmap lookup.
          * Return a new image::Image, caller should delete it.

examples/nn_yolo26_depth/main/src/main.cpp

@@ -2,11 +2,11 @@
  * YOLO26-depth example
  *
  * Usage:
- *   - 单张图片推理并保存热力图:
- *       ./nn_yolo26_depth mud_model_path image_path [output_path]
- *       例: ./nn_yolo26_depth /tmp/yolo26n-depth.mud /tmp/bus.jpg /tmp/bus_heatmap.jpg
- *   - 实时摄像头推理并显示热力图:
- *       ./nn_yolo26_depth mud_model_path
+ *   - 单张图片推理并保存热力图(可选传 cal_a cal_b 校准):
+ *       ./nn_yolo26_depth mud_model_path image_path [output_path] [cal_a cal_b]
+ *       例: ./nn_yolo26_depth /tmp/yolo26n-depth.mud /tmp/bus.jpg /tmp/bus_heatmap.jpg 0.85 0.40
+ *   - 实时摄像头推理并显示热力图(可选传 cal_a cal_b):
+ *       ./nn_yolo26_depth mud_model_path [cal_a cal_b]
  *       点击画面可添加/取消距离探针，最多保留 5 个，距离随画面实时更新。
  *
  * 依赖(设备上需存在):
@@ -166,6 +166,15 @@ int _main(int argc, char *argv[])
     const char *model_path = argv[1];
     bool dual_buff = false;
     image::CMap cmap = image::CMap::JET;
+    // 可选深度校准参数(默认不校准): d_real = exp(cal_a * log(d_raw) + cal_b)
+    float cal_a = 1.0f;
+    float cal_b = 0.0f;
+    if (argc >= 6)
+    {
+        cal_a = std::stof(argv[4]);
+        cal_b = std::stof(argv[5]);
+        log::info("depth calibration enabled: cal_a=%f cal_b=%f", cal_a, cal_b);
+    }
 
     log::info("model path: %s", model_path);
     nn::YOLO26Depth model(model_path, dual_buff);
@@ -189,8 +198,8 @@ int _main(int argc, char *argv[])
                       img->width(), img->height(), model.input_width(), model.input_height());
         }
 
-        // 推理得到深度热力图(自动 resize 回原图尺寸)
-        maix::image::Image *heatmap = model.get_depth_image(*img, image::FIT_CONTAIN, cmap);
+        // 推理得到深度热力图(自动 resize 回原图尺寸; 可传 cal_a/cal_b 校准)
+        maix::image::Image *heatmap = model.get_depth_image(*img, image::FIT_CONTAIN, cmap, cal_a, cal_b);
         err::check_null_raise(heatmap, "get_depth_image failed");
 
         // 保存热力图
@@ -246,7 +255,7 @@ int _main(int argc, char *argv[])
                 was_pressed = pressed;
             }
 
-            std::unique_ptr<tensor::Tensor> depth(model.get_depth(*img, image::FIT_CONTAIN));
+            std::unique_ptr<tensor::Tensor> depth(model.get_depth(*img, image::FIT_CONTAIN, cal_a, cal_b));
             if (!depth)
                 continue;